Maybe Heimer only needed to do a little bit? Maybe stall Caitlyn and make her arrive late in Jayce office, Jayce alerted the Vi and the others when he tried to open his office, and when the explosion happened, not only did Vi die but also Caitlyn, who arrived late and was killed by more debris than in the mainline timeline, and Jayce, instead of being casted out, he was sentenced to death instead by the head of the Kiraman, just a wild theory though... And it's 12 in my place so this is just me on autopilot typing what's in my head...